Growth hormone and ACTH in the pituitary of normal and anencephalic human fetuses: immunocytochemical evidence for hypothalamic influences during development.

The influence of the hypothalamus on the development of the anterior pituitary cells was studied in normal and anencaphalic human fetuses. An immunocytological method was applied to study the quantitative evolution of the size of the cells during gestation. The somatotropic and corticotropic cells appeared at the end of the 2nd month of gestation. After the 3rd month of gestation their normal development required the presence of brain. The results suggest that hypothalamic factors are needed for the normal development of cells containing these pituitary hormones.